Need help re anodizing

h1v9a8c8

Member
I just picked this up off ebay. I put a boi I had on it but need help finding someone who ca re anodize the stem and crank arm. Any help would be great.
 

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mainlyfats

Member
Paul Components has been doing some pretty intense anodizing lately, someone there might have a lead or let you in on a batch.
 

Stingercut

Active member
Has anybody tried to re-anodise a set of Grafton Speed Controller cantis or similar ? The Graftons have brass and steel components.

If so how did it turn out ?
 

jpicard616

New member
You cannot anodize brass or steel. The dying process only works for aluminum (titanium anodizing is a completely different process). That being said, the acid bath that parts go through for the anodizing process won't hurt little steel or brass parts, but those parts should be removed beforehand if possible so as not to cover up any of the aluminum and thus prevent the coloring of certain areas.
 

Stingercut

Active member
This sounds promising but the brass tube which fits over the brake boss, which is press fit into the canti arm, can't be removed.

I was concerned about this statement.

"Anything that isn't aluminium that is anodised will be dissolved so needs to be removed first! Some things can be sealed such as a ratchet ring in a rear hub, it's very time consuming though so please ask first!"

From here - intrincycle.co.uk - click on anodising link

If it is an issue what's the best method to shield the brass component to prevent it being dissolved ?
 

jpicard616

New member
Oh ok. I thought you were talking about a little metal o-rings. Any part you dip in acid will corrode to some extent, but I doubt they will dissolve. So that brass tube that fits over the canti boss (I haven't seen Grafton's up close, but I'm assuming they're similar to Paul's) will get etched on every surface that comes in contact with the acid. If that happens, then they wouldn't fit nearly as well on the canti studs as they did before the acid bath.

In your case I would recommend not anodizing your brakes until you can find a way to press out those brass bushings, especially considering the rarity of those brakes... you wouldn't want to ruin them!
 

zonq

Member
I anodized my Graftons. ...sort of.

There is a bit of bother about those bushes. If you take the bushing out, and anodize the arm, when they strip it and electropolish it, it removes some thickness of metal off the surface, and how much depends on how long they leave it in, and how long they leave it in is entirely up to a multitude of factors. So afterward, when they anodize it again, and grow the oxide layer, that thickness isn't exactly the same. Plus, there'll be some wear in pushing them back in again... So there's a chance your bushings will be loose. If you leave the bushing in, it'll etch away at your brass and open up the ID of the bushing, which will then fit loose on the stud.

so I cheated and just anodized the L brackets, spring covers, & face plates (which actually came off another mismatched set anyway) to match the rest of the bike, avoiding any trouble with the bushings at all.
139667518641.jpg

plz excuse the badly lit basement-at-night pic

But I have ano'd a few things with stainless steel inserts (bonded bolts & rivets) in them, to no negative effect.
 

Stingercut

Active member
I anodized my Graftons. ...sort of.

There is a bit of bother about those bushes. If you take the bushing out, and anodize the arm, when they strip it and electropolish it, it removes some thickness of metal off the surface, and how much depends on how long they leave it in, and how long they leave it in is entirely up to a multitude of factors. So afterward, when they anodize it again, and grow the oxide layer, that thickness isn't exactly the same. Plus, there'll be some wear in pushing them back in again... So there's a chance your bushings will be loose. If you leave the bushing in, it'll etch away at your brass and open up the ID of the bushing, which will then fit loose on the stud.

so I cheated and just anodized the L brackets, spring covers, & face plates (which actually came off another mismatched set anyway) to match the rest of the bike, avoiding any trouble with the bushings at all.
139667518641.jpg

plz excuse the badly lit basement-at-night pic

But I have ano'd a few things with stainless steel inserts (bonded bolts & rivets) in them, to no negative effect.

Thanks for clearing this all up ! This is what I thought would happen and you have confirmed the issues. Useful to know that SS is ok during this process.Btw how did you remove and reinsert the brass bushing into the arm ?
 

zonq

Member
Thanks for clearing this all up ! This is what I thought would happen and you have confirmed the issues. Useful to know that SS is ok during this process.Btw how did you remove and reinsert the brass bushing into the arm ?

When I have to press things out, I just find a rod slightly smaller than the bushings OD, & press them out with a hydraulic press. When reinserting them, freeze the bushing overnight and then insert it. Reduces the wear on the aluminum while pressing in.
 

Stingercut

Active member
When I have to press things out, I just find a rod slightly smaller than the bushings OD, & press them out with a hydraulic press. When reinserting them, freeze the bushing overnight and then insert it. Reduces the wear on the aluminum while pressing in.

Thanks for that. Interesting, I thought the bushing would be pushed out after heating up the whole unit first, maybe with a heat gun, taking advantage of the differential expansion rates of Alu and brass before pressing the brass bush out.
 

Chris

New member
Steel will dissolve. I've never had a problem with stripping anodising with brass inserts. It doesn't affect it like it does with aluminium.
Stainless steel does dissolve, I've had sulphuric acid burn through the bottom of a stainless container. It also gives off toxic chronic acid IIRC.
 

Stingercut

Active member
Steel will dissolve. I've never had a problem with stripping anodising with brass inserts. It doesn't affect it like it does with aluminium.
Stainless steel does dissolve, I've had sulphuric acid burn through the bottom of a stainless container. It also gives off toxic chronic acid IIRC.

Is this Chris from Intrincycle ? :) hope it is.

This is an interesting thread with some conflicting opinion. We need to ensure the intel is 100% factually correct based on empiricle evidence. These parts aren't cheap and we don't want anybody trashing components unsuspectingly.
 

zonq

Member
Yeah, it's tricky. Depends on what it is specifically and the process too. I recently had a little stainless insert in an aluminum part that burned the aluminum up around it pretty badly. But we also did a run of parts recently that all had these tiny steel bolts that couldn't be removed, which came through fine. ...I'd have to ask my guy what the story was with the bolts. Maybe they were plated. He's the chemist, I'm not, & I'd defer to Chris' experience as well.

Anyway, without knowing specific metals in any of these old bike parts, it's kind of a crapshoot stripping & reanodizing them sometimes. Never try reanodizing marinovative cheap trick brakes, for instance. A truly horrible alloy.
 

Chris

New member
Yes it's me :)

It would be interesting to know what the bolts were, perhaps they were electrically insulated from the aluminium being anodised somehow?

As you say alloy varies greatly, I've found some parts that are anodised black are hiding faults in the material. 6061 & 6083 comes out the best as it has a huger percentage of aluminium. The most easily available grade in the UK is 6082 (in USA too?) is almost as good.

I'm not really anodising anything at the moment as I'm too busy.

Ringle stuff is generally quite good, except the QR nuts which pitt.

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